2024 CSDMS meeting-104


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Remote sensing constrains model inputs in a real-world delta

Julianne Davis, University of North Carolina at Chapel Hill Chapel Hill North Carolina, United States. jmsdavis@unc.edu
Tamlin Pavelsky, University of North Carolina at Chapel Hill Chapel Hill North Carolina, United States.
Doug Edmonds, Indiana University Bloomington Bloomington Indiana, United States.

Field-based studies, remote sensing analyses, and model development inform our understanding of patterns and processes in incipient delta formation and continued progradation. Rarely, however, have the three approaches been used together to understand the entire progradation history of a real-world system. This may be largely due to the paucity of appropriate sites: an accessible location where a delta has been growing for just a few decades. One site that meets these criteria is Mamawi Creek delta, located within the larger Peace Athabasca Delta ecosystem in northeastern Alberta, Canada. Mamawi Creek delta began forming in 1982, just two years before the beginning of Landsat TM observations over boreal Canada. Due to strong scientific interest and human presence in the region, data on sediment, flow, water levels, and elevations have been collected for decades. Here, we use these available field data to create a site-specific morphodynamic model of Mamawi Creek Delta in Delft3D. Leveraging discoveries from previous modeling studies that have examined how inputs, such as percent of cohesive sediment and median grain size, affect resulting delta forms, we approach the inverse question to see how observed delta characteristics in the Landsat record can constrain model setup and inputs. By comparing annual model outputs against remotely sensed observations of true delta form over the last 40 years, we learn the limitations of our field data and consequences of model simplifications. We then iteratively use these comparisons to inform model parameter adjustments and changes to boundary conditions that enhance agreement between these two methods, ultimately producing a simulated delta that acceptably mimics observed progradation.